JP2009300960A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress replacing frequency of a toner cartridge, occurring frequency of jamming and consumption of color-less toner, to improve work efficiency when creating confidential documents, and to save cost. <P>SOLUTION: A plurality of developing devices filled with a plurality of kinds of color toner and color-less toner containing visible light absorbing material are mounted in the image forming apparatus. In the image forming apparatus, an image pattern for restricting a toner conveying capacity of a color-less toner image is selected when it is determined that a toner conveying capacity of a color toner image is large. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image forming apparatus that makes it impossible to copy a specific confidential document to prevent information leakage.

  Conventionally, for the purpose of prohibiting or suppressing copying of forms and resident's cards, these contents have been printed on a specially-printed paper called anti-counterfeit paper. This forgery-preventing paper is hard to be seen by humans in the original, but is a paper on which characters such as “prohibited copying” appear when copying using a multifunction machine or the like. As a result, the effect of making the copy person hesitant to use the copy is produced. Furthermore, it is assumed that such a form or the like is printed on forgery prevention paper, so that the effect of inhibiting and checking the copy itself is also produced. However, such anti-counterfeit paper has a problem that it is more expensive than ordinary paper.

  As a technique for prohibiting copying, for example, techniques described in Patent Document 1, Patent Document 2, and Patent Document 3 are known.

  The technology described in Patent Document 1 is an organic compound having a reversible phenomenon called photochromism that changes color when a substance is irradiated with light, and reverses color when the changed substance is irradiated or heated with other light. Copying is prevented by using a copy-preventing printing material containing as a component.

  In addition, the technique described in Patent Document 2 is a technique that allows a copy-preventing medium having a color-developing layer containing a photochromic compound that is difficult to decolorize by ultraviolet light on the entire surface or a part of the surface before the document reading process. The step of irradiating the entire surface of the original with ultraviolet light is performed.

On the other hand, the technique described in Patent Document 3 is provided with an invisible image on the surface of an image output medium using an electrophotographic toner containing a binder resin and a near-infrared light absorbing material made of inorganic material particles. When a visible image is viewed, an invisible image that can be provided in an arbitrary region is obtained regardless of the region where the visible image is provided on the surface of the image output medium without impairing the image quality of the visible image.
JP-A-6-279721 JP 2006-243100 A JP 2003-186238 A

  However, the prior art described in the above publication has the following problems. In other words, the technique described in Patent Document 1 does not define anything about the region to which the toner having the photochromism phenomenon is added, and when this toner is always image-formed on the entire surface, the amount of toner consumed is changed to other coloring. The problem is much more expensive than toner, and the cost is high, and the toner cartridge is frequently emptied, so the user has to change the toner cartridge frequently and bother the user. Become.

  In the technique described in Patent Document 2, a mechanism for irradiating ultraviolet light before the document reading process is provided in the copying apparatus, which is not appropriate in terms of cost. Further, the lamp for generating ultraviolet light is not good for human eyes, and a pressure plate made of a member having a blocking property against ultraviolet light is used as a pressure plate for bringing the document into close contact with the document table. It is necessary to additionally provide a mechanism that does not operate in a state where it is not in close contact with the table, and there is a problem that the cost is further increased.

  On the other hand, in the technique described in Patent Document 3, the absorbability in the visible light region of the toner that forms an invisible image is described, but the invisible image and the visible image are sequentially stacked on the surface of the image output medium. When printing an image with a large amount of toner consumption such as a full-scale photo image on a paper with a small basis weight, the toner shrinks over time and the paper It may curl up and jam may occur.

  The present invention has been made paying attention to the above-described problems, and suppresses the toner cartridge replacement frequency, the occurrence frequency of jamming, and the consumption amount of colorless toner, and improves the working efficiency when creating a confidential document. An object of the present invention is to provide an image forming apparatus capable of saving costs.

  In view of the above points, according to the image forming apparatus of the present invention, the following disadvantages are eliminated by taking the following measures.

  That is, the image input means for inputting image data, the image processing means for performing image processing on the image data input by the image input means, and the video data of the image processed by the image processing means are counted. A plurality of video data counting means, a toner amount calculating means for calculating the amount of toner used from the video data counting means, one or more image carriers, a plurality of colored toners, and a colorless toner containing a visible light absorbing material And an image forming unit that develops the image carrier exposed by the exposure unit with the developing unit to form an image. The exposure unit performs exposure for forming an electrostatic latent image on the image carrier. A color toner calculated by the toner amount calculating unit in an image forming apparatus that prints an image formed by the image forming unit on an image recording medium and outputs the image; When the toner amount of the image exceeds a threshold indicating a limit, it is characterized in that an image is formed for limiting the amount of toner colorless toner image.

  As described above, according to the present invention, in an image quality forming apparatus equipped with a plurality of developing devices filled with a plurality of colored toners and a colorless toner containing a visible light absorbing material, the toner loading amount of colored toner images is large. If it is determined, the image pattern for limiting the toner loading amount of the colorless toner image is selected, so that the replacement frequency of the toner cartridge, the occurrence frequency of the jam, and the consumption amount of the colorless toner are suppressed, and the confidential document is created. The work efficiency can be improved and the cost can be saved.

  Next, details of the present invention will be described in accordance with the description of the embodiments.

  Embodiments of the present invention will be described below with reference to the drawings. The present invention is not limited to this embodiment.

  FIG. 1 is a block diagram showing the overall configuration of an image forming apparatus according to an embodiment of the present invention.

  A reader device (reader unit) 300 optically reads a document image and converts it into image data. The reader unit 300 includes a scanner unit 210 having a function for reading a document and a document feeding unit 250 having a function for transporting a document sheet. The document feeding unit 250 is not necessarily required as an optional unit.

  A printer apparatus (printer unit) 100 conveys recording paper, prints image data as a visible image thereon, and discharges the recording paper outside the apparatus. The printer unit 100 includes a paper feed unit 310 having a plurality of types of recording paper cassettes, a marking unit 320 having a function of transferring and fixing image data onto the recording paper, and sorting and stapling the printed recording papers. And a paper discharge unit 330 having a function of outputting to The paper discharge unit 330 is not necessarily required as an optional unit.

  The control device (controller unit) 110 is electrically connected to the reader unit 300 and the printer unit 100, and is further connected to the computer 101 via the network 400. The controller unit 110 also controls the reader unit 300 to read image data of a document, and controls the printer unit 100 to output the image data to a recording medium to provide a copy function. Also, a scanner function that converts image data read from the reader unit 300 into code data and transmits the code data to a computer via the network 400. Code data received from the computer via the network 400 is converted into image data, and a printer unit. A printer function for outputting to 100 is provided.

  The operation unit 170 is connected to the controller unit 110 and is configured by a liquid crystal touch panel, and provides a user I / F for operating the image forming apparatus. By using the operation unit 170, the user can perform print settings for adding a transparent toner image to an arbitrary area of a colored toner image or print settings for a general document that is not subject to copy prevention on the image forming apparatus. It becomes. Here, as the area to which the transparent toner image is added, for example, a character area, an image area, or a character / image area of a colored toner image can be set.

  FIG. 2 is a schematic sectional view of an image forming apparatus according to an embodiment of the present invention.

  The image forming apparatus includes a digital color image reader unit 300 at the top and a digital color image printer unit 100 at the bottom.

  In the reader unit 300, the original 30 is placed on the original table glass 31 and exposed and scanned by the exposure lamp 32, so that the reflected light image from the original 30 is condensed on the full-color CCD sensor 34 by the lens 33, and color color separation is performed. An image signal is obtained. The color-separated image signal passes through an amplifier circuit (not shown), is subjected to image processing such as input masking in the input image processing unit 150 shown in FIG. 3, and then is transferred to the hard disk 162 via the image memory (DRAM) 116. Temporarily stored. The image data read from the hard disk 162 is subjected to image processing by the output image processing unit 151 and sent to the printer unit 100.

  In addition to the signal from the reader unit 300, the image signal from the computer 101 and the image signal from the FAX shown in FIG. Here, as a representative example, an operation in the printer unit 100 based on a signal from the reader unit 300 will be described.

  In the printer unit 100, an image forming unit 2 including a photosensitive drum 1 is disposed. A drum-shaped photosensitive member (photosensitive drum) 1 serving as an image carrier is rotatably supported in the direction of an arrow in the figure, and around it, a pre-exposure lamp 11, a corona charger (charging means) 3, and a laser exposure optical system. Exposure means 4, potential sensor 12, movable body (development rotary) 5 that is a rotary developing device holding portion, and six developing devices 501 to 506 that contain developers of different colors in the holding portion, primary transfer A primary transfer roller 6 and a cleaning device 7 are arranged as means.

  The developing device 501 is loaded with cyan toner, 502 with magenta toner, 503 with yellow toner, 504 with black toner, 505 with light black toner, and 506 with transparent toner.

The developer will be described in detail. As the colored toner, a toner having a volume average particle diameter of about 8 μm obtained by pulverizing and classifying a resin binder mainly composed of polyester and kneading a pigment is used. Further, in this embodiment, the light black toner, which is a light color toner, is produced by reducing the number of pigment parts contained in the black toner, which is a dark color toner. Here, in addition to the light black toner, a developing device (same shape as the above developing device) that accommodates a toner having a spectral characteristic different from that of cyan, magenta, yellow, and black, such as metallic toners such as gold and silver. Can be mounted on the developing rotary 5. The transparent toner has a maximum absorption rate of 15% or less in the visible light region (400 nm to 700 nm) and an average dispersion diameter of inorganic material particles containing at least CuO and P ₂ O _{5 in} the range of 50 nm to 800 nm. It is preferable that the resin is the same as the colored toner and becomes transparent after fixing. In addition, since the area to which the transparent toner is added on the recording medium absorbs the wavelength of the visible light area during copying, a part of the area is printed in black on the copy of the recording medium.

  In addition, although the two-component developer used by mixing the toner and the carrier is loaded in the developing device, there is no problem even with the one-component developer including only the toner.

  In the laser exposure optical system 4 that is an exposure means, the image signal from the reader unit 300 is converted into an optical signal by a laser output unit (not shown), and the laser beam 8 converted into the optical signal is reflected by the polygon mirror 35. Then, the light is projected onto an exposure position 38 on the surface of the photosensitive drum 1 through the lens 36 and the reflecting mirrors 37.

  First, at the time of image formation by the printer unit 100, the photosensitive drum 1 is rotated in the direction of the arrow, and the photosensitive drum 1 after being neutralized by the pre-exposure lamp 11 is uniformly charged by the charger 3 for each separation color. A light image 8 is irradiated to form a latent image on the photosensitive drum 1.

  Next, after rotating the rotary developing device holding section, that is, the developing rotary 5, which is a moving body, the predetermined developing device 501 is moved onto the photosensitive drum 1, the developing device 501 is operated, and the photosensitive drum 1 is moved. The electrostatic latent image is reversely developed to form a developer image (toner image) on the photosensitive drum 1 using a resin and a pigment as a base. At this time, a developing bias is applied to the developing device. As shown in the figure, the toner in the developing units 501 to 506 is the toner ratio (or toner amount) in the developing unit from the toner storage units (hoppers) 61 to 66 for each color arranged on the laser exposure optical system 4. So as to keep constant at a desired timing.

  The toner images formed on the photosensitive drum 1 are sequentially primary so that the toner images are formed on the intermediate transfer body (intermediate transfer belt) 508 as a transfer medium by a primary transfer roller 6 serving as a primary transfer unit. Transcribed. At this time, a primary transfer bias is applied to the primary transfer roller 6. As a result, a toner image of cyan toner, magenta toner, yellow toner, black toner, light black toner, and transparent toner is sequentially superimposed on the intermediate transfer belt 508 to form a full color toner image.

  Thereafter, the full-color toner image on the intermediate transfer belt 508 serving as a transfer medium is secondarily transferred collectively onto a sheet as a recording medium. At this time, a secondary transfer bias is applied to the secondary transfer roller 54.

  The intermediate transfer belt 508 is driven by the drive roller 51, and the transfer cleaning device 50 is configured to be able to contact and separate from the drive roller 51 at a position facing the intermediate transfer belt 508.

  The photosensitive drum 1 is provided on a transfer surface 509 that is the same plane portion formed by stretching the intermediate transfer belt 508 by two rollers 51 and 52, and the intermediate transfer belt 508 with the photosensitive drum 1 is sandwiched between the photosensitive drum 1 and the transfer surface 509. A primary transfer roller 6 serving as a primary transfer unit is provided at the opposite portion.

  In addition, a sensor 53 that detects the positional deviation and density of the image transferred from the photosensitive drum 1 is disposed opposite to the driven roller 52 on the downstream side in the moving direction of the intermediate transfer belt 508 among the rollers that form the transfer surface 509. As necessary, each image forming unit 2 is controlled to correct the image density, toner replenishment amount, image writing timing, image writing start position, and the like.

  Also, the transfer cleaning device 50 facing the upstream drive roller 51 finishes superimposing necessary images on the intermediate transfer belt 508, and then pressurizes the opposing drive roller 51 to transfer it to a recording medium. Residual toner on the intermediate transfer belt 508 is cleaned. After cleaning, the transfer cleaning device 50 is separated from the intermediate transfer belt 508.

  On the other hand, the recording medium is conveyed one by one from the storage units 71, 72, 73 or the manual feed tray 74 by the respective paper feeding means 81, 82, 83, 84, and the skew is corrected by the registration rollers 85, and desired At this timing, the toner image on the intermediate transfer belt 508 is conveyed to a secondary transfer portion between the secondary transfer roller 54 and the intermediate transfer belt 508, which is a secondary transfer means for transferring the toner image onto the recording medium.

  The toner image is transferred onto the recording medium in the secondary transfer unit, the recording medium passes through the conveying unit 86, and the toner image is fixed by the heat roller fixing device 9, and the paper discharge tray 89 or the post-processing device of the recording medium ( (Not shown).

  On the other hand, the intermediate transfer belt 508 after the secondary transfer is cleaned with the transfer residual toner by the transfer cleaning device 50 as described above, and again used for the primary transfer process of the image forming unit 2.

  Further, when forming images on both sides of the recording medium, the conveyance path switching guide 91 is driven immediately after the recording medium passes through the fixing device 9, and the recording medium is temporarily connected to the reverse path 76 via the conveyance vertical path 75. After being guided, the reverse roller 87 is rotated in the reverse direction so that the trailing edge of the recording medium at the time of feeding is set at the top, and the recording medium is withdrawn in the direction opposite to the fed direction, and is sent to the duplex conveying path 77. After that, the paper passes through the double-sided conveyance path, skew correction and timing are performed by the double-sided conveyance roller 88, and are conveyed to the registration roller 85 at a desired timing. Is transferred and output.

  The function of the controller unit 110 will be described based on the block diagram of the controller unit shown in FIG.

  The main controller 111 mainly includes a CPU 112, a bus controller 113, and various I / F controller circuits.

  The CPU 112 and the bus controller 113 control the overall operation of the controller unit 110, and the CPU 112 operates based on a program read from the ROM 114 via the ROM I / F 115. The operation of interpreting PDL (page description language) code data received from a computer and developing it into raster image data is also described in this program and processed by software. The bus controller 113 controls data transfer input / output from each I / F, and performs arbitration at the time of bus contention and control of DMA data transfer.

  The DRAM 116 is connected to the main controller 111 by a DRAM I / F 117 and is used as a work area for the CPU 112 to operate and an image memory for storing image data.

  The Codec 118 has a function of compressing raster image data stored in the DRAM 116 by a method such as MH / MR / MMR / JBIG, and conversely decompressing the code data compressed and stored into raster image data.

  The SRAM 119 is used as a temporary work area of the Codec 118. The Codec 118 is connected to the main controller 111 via the I / F 120, and data transfer to and from the DRAM 116 is controlled by the bus controller 113 and is DMA-transferred.

  The network controller 121 is connected to the main controller 111 through an I / F 123 and is connected to an external network through a connector 122. The network is generally Ethernet (registered trademark).

  An expansion connector 124 for connecting an expansion board and an I / O control unit 126 are connected to the general-purpose high-speed bus 125. A general-purpose high-speed bus is a PCI bus.

  The I / O control unit 126 is equipped with two channels of an asynchronous serial communication controller 127 for transmitting / receiving control commands to / from each of the CPUs of the reader unit 300 and the printer unit 100. F circuits 140 and 145 are connected.

  The panel I / F 132 is connected to the LCD controller 131 and includes an I / F for displaying on a liquid crystal screen on the operation unit 170 and a key input I / F 130 for inputting hard keys and touch panel keys. Is done. The operation unit 170 includes a liquid crystal display unit, a touch panel input device attached on the liquid crystal display unit, and a plurality of hard keys. A signal input from the touch panel or hard key is transmitted to the CPU 112 via the panel I / F 132 described above, and the liquid crystal display unit displays image data sent from the panel I / F 132. The liquid crystal display unit displays function display, image data, and the like in the operation of the image forming apparatus.

  The real-time clock module 133 is for updating / saving the date and time managed in the device, and is backed up by a backup battery 134.

  The E-IDE connector 161 is for connecting an external storage device. The hard disk drive 160 is connected via this I / F, and image data and image information attached to the image data can be stored in the hard disk 162, and image data can be read from the hard disk 162.

  The connectors 142 and 147 are connected to the reader unit 300 and the printer unit 100, respectively, and are composed of a synchronized step-synchronized serial I / F (143, 148) and a video I / F (144, 149).

  The scanner I / F 140 is connected to the reader unit 300 via the connector 142, and is connected to the input image processing unit 150 and the main controller 111 via the scanner bus 141.

  The input image processing unit 150 will be described with reference to the block diagram of the input image processing unit in FIG.

  First, the R (Red), G (Green), and B (Blue) signals of the original image input from the CCD sensor 34 of the reader unit 300 are input to an analog signal processing unit (not shown), and white level and black level. After the correction process, the analog / digital conversion is performed by the A / D conversion unit 401 and the signal digitized by the shading correction unit 402 is subjected to shading correction (variation of sensors such as a CCD for reading a document and document illumination). Correction of the light distribution characteristics of the lamp for the light source) is performed, and image area processing unit 403 adds image area information for each pixel of the image.

  As shown in FIG. 5, the image area information is information added with 8 bits for each pixel of the image separately from the image data, and each bit is a setting at the time of scanning, a color mode setting of the operation unit 170, a document. Determine from type and resolution. For example, the 7th bit of the image area information indicates whether the pixel is color or black and white, and the 6th bit indicates whether the pixel is a character or an image. The information indicates that the input is SCAN or PDL, the output destination is FAX or COPY, the color space is RGB or CMYK, the image is non-image, and the resolution is 600 dpi or 300 dpi. In the present invention, the character area and the image area of the image data input to the image forming apparatus are discriminated by referring to the character / image bit information of the sixth bit among the image area information.

  Thereafter, the sampling unit 404 shown in FIG. 4 performs sampling processing of image data to be used for background level adjustment. Next, after filter processing is performed by the filter processing unit 405, trimming processing is performed on unnecessary portions of the image data by the trimming unit 406 and is stored in the DRAM 116 shown in FIG. Note that data transfer from the scanner bus 141 to the DRAM 116 is controlled by the bus controller 113.

  The image processing unit 152 is connected to the main controller 111 by a video I / F 153, reads an image stored in the DRAM 116 and performs image processing, and the processed image is stored in the DRAM 116 again.

  The image processing unit will be described with reference to the block diagram of the image processing unit in FIG.

  The image read from the DRAM 116 is scaled according to the setting value specified by the scaling processing unit 701, and the image rotating unit 702 performs a rotation process according to the paper. The color processing unit 703 performs color space conversion processing from a binary image to multi-value conversion for printing. The video count unit 704 calculates the toner consumption amount from the video data of the image. This video count unit receives 8-bit data for each color of R, G, and B. The data value of each color for each pixel is integrated, the toner consumption is calculated from the integrated value, and divided by the paper size. The amount of toner loaded per unit area is calculated. The image output from the video count unit is stored in the DRAM 116 again.

  The printer I / F 145 is connected to the printer unit 100 via the connector 147, and is connected to the output image processing unit 151 and the main controller 111 via the printer bus 146.

  The output image processing unit 151 will be described with reference to the block diagram of the output image processing unit in FIG.

  First, when image data for output is read from the DRAM 116, the background processing unit 601 performs background level correction processing of the image data, and the color adjustment unit 602 performs hue adjustment and saturation adjustment specified by the operation unit 170. Image processing such as color space compression is performed.

  Next, in the transparent toner image generation unit 609, based on the area to which the transparent toner image set by the operation unit 170 or the driver of the computer 101 is added and the image area information added by the image area processing unit 403 shown in FIG. In addition, a transparent toner image as shown in FIG. 8 is generated.

  FIG. 8 is a diagram illustrating an example of a transparent toner image generated by the transparent toner image generation unit 609. A print setting for adding transparent toner to a character area of a colored toner image is performed from the operation unit 170 or the driver of the computer 101. If it is broken, a transparent toner image added only to the character area is generated. On the other hand, when print setting for adding transparent toner to the image area of the colored toner image is performed from the operation unit 170 or the driver of the computer 101, a transparent toner image to be added only to the image area is generated. As shown in FIG. 8, when generating a transparent toner image of an image area, the toner stacking amount of the image area can be adjusted by controlling the printing interval of the transparent toner. In addition, the image pattern of the transparent toner in the present invention is not limited to this. For example, a vertical line image, a horizontal line image, or a stripe image may be used.

  After that, the composition unit 603 shown in FIG. 7 performs composition processing of the transparent toner image and the colored toner image subjected to image processing by the color adjustment unit 602.

  Then, after the LOG conversion processing is performed by the LOG conversion unit 604, the direct mapping unit 605 converts R, G, B to C (cyan), M (magenta), Y (yellow), K (black), Lk (light Luminance → density conversion processing to black) is performed. Here, it is assumed that no processing is performed on the W (transparent toner) signal in the LOG conversion unit 604 and the direct mapping unit 605.

  The Y, M, C, K, Lk, and W signals output from the direct mapping unit 605 are subjected to γ processing by the γ (density) correction unit 606, and then screen processing is performed by the screen processing unit 607. The screen-processed image data is trimmed by the trimming unit 608 according to the printable area.

  Transfer of raster image data developed on the DRAM 116 to the printer unit 100 is controlled by the bus controller 113, and DMA-transferred to the printer unit 100 via the printer bus 146 and the video I / F 149.

  FIG. 9 is a diagram showing an example of a copy of the recording medium output by the image forming apparatus according to the embodiment of the present invention. If transparent toner is not added, the copy of the recording medium can be recognized. However, if the transparent toner is set to be added to the character area of the colored toner image, characters are printed on the copy of the recording medium. The area becomes unrecognizable. On the other hand, when setting is made to add transparent toner to the image area of the colored toner image, the image area cannot be recognized on a copy of the recording medium. Further, when setting is made to add transparent toner to the character / image area of the colored toner image, the character / image area cannot be recognized on the copy of the recording medium.

  Next, an operation when an image is input from the reader unit 300 or the computer 101 via the network 400 in the copy operation and output to the recording medium by the printer unit 100 will be described with reference to the flowchart of FIG. S1001 to S1016 in this flowchart indicate each step.

  In the case of copying, first, in the operation unit 170, a region to which a transparent toner image is to be added, a variable magnification, the number of output copies, the size of the output recording medium and the type of the recording medium are set, and then the document 30 is placed on the document table glass 31. When the start key is pressed, an output start instruction is issued to the reader unit 300 and the printer unit 100. On the other hand, in the case of PDL output, in order to output an image created by the computer 101 connected to the network 400 by the image forming apparatus, an instruction to start output is issued from the driver of the computer 101 (S1001).

  When an instruction to start image output is issued, in the case of copying, the original is exposed and scanned by the exposure lamp 32, and the image is input by reading the image with the CCD. On the other hand, in the case of PDL output, PDL (page description language) code data is transmitted from the computer 101, and the image forming apparatus receiving it interprets the code data by the CPU 112 and converts it into raster image data (S1002). .

  The input image is subjected to input image processing such as input masking processing, filter processing, and image area information addition in the input image processing unit 150 (S1003). Next, image processing is performed by the image processing unit 152, and image processing such as scaling, rotation, and color processing is performed (S1004). At this time, the video count unit 504 counts the video data of R, G, and B colors, and calculates the toner loading amount per unit area by dividing the toner consumption calculated from the integrated value by the paper size. (S1005). The toner loading amount per unit area of each original is temporarily stored in the SRAM 119, and the image processed image is stored in the DRAM 116 in the image forming apparatus (S1006).

Next, it is determined whether or not the print setting instructed from the operation unit 170 or the driver of the computer 101 is a setting for adding a transparent toner image to the image area of the colored toner image (S1007). When it is determined that the setting is to add a transparent toner image to the image area of the colored toner image, the toner loading amount per unit area calculated previously is read from the SRAM 119, and the toner loading amount is set to a predetermined threshold value. For example, a determination process is performed as to whether or not it exceeds 20 g / m ² (S1008). If it is determined that the toner loading amount exceeds a predetermined threshold, it is determined that the toner loading amount of the colored toner image is large, the transparent toner printing interval is set large, and the toner loading amount of the transparent toner image is limited. An image pattern to be selected is selected (S1009). On the other hand, if it is determined in step S1008 that the toner loading amount does not exceed the threshold value, an image pattern in which the clear toner printing interval is set is selected (S1010).

  Next, a determination process is performed to determine whether the print setting instructed by the operation unit 170 or the driver of the computer 101 is a setting for adding a transparent toner image to the character area of the colored toner image (S1011). If it is determined that the transparent toner image is set to be added to the character area of the colored toner image, the transparent toner image generation unit 609 uses the character area / character information based on the image area information added by the image area processing unit 403. A transparent toner image of the image area is generated (S1012), and the image held in the DRAM 116 is read out for printing (S1016). On the other hand, if it is determined in step S1011 that the transparent toner image is not added to the character area of the colored toner image, based on the image area information added by the image area processing unit 403, the transparent toner image generating unit In 609, a transparent toner image of the image area is generated (S1013).

  If it is determined in step S1007 that the setting is not to add the transparent toner image to the image area of the colored toner image, a determination process is performed to determine whether the setting is to add the transparent toner image to the character area of the colored toner image. (S1014). If it is determined that the setting is to add the transparent toner image to the character area of the colored toner image, the transparent toner image generation unit 609 determines the character area based on the image area information added by the image area processing unit 403. A transparent toner image is generated (S1015). On the other hand, if it is determined in step S1014 that the transparent toner image is not added to the character area of the colored toner image, the transparent toner image is not generated and the process proceeds to step S1016, and the image held in the DRAM 116 is printed. Read for.

  After the image held in the DRAM 116 is read, output image processing such as background processing, color adjustment, and synthesis of a colored toner image and a transparent toner image is performed in the output image processing unit 151 (S1017).

  After the output image processing is performed, it is sent to the printer unit 100, converted into an optical signal according to the image data, exposed to a drum with a laser, developed with a developing device, and then output to an image recording medium ( S1018). If there is a next image, the same processing is performed and repeated until all the images are output (S1019). When all the images have been output, the process ends.

1 is a block diagram illustrating an overall configuration of an image forming apparatus according to an embodiment of the present invention. 1 is a schematic cross-sectional view of an image forming apparatus according to an embodiment of the present invention. 2 is a block diagram illustrating a controller unit of the image forming apparatus. FIG. It is a block diagram which shows the structure of an input image processing unit. It is a figure which shows the image area information of an image. It is a block diagram which shows the structure of an image processing unit. It is a block diagram which shows the structure of an output image processing unit. FIG. 4 is a diagram illustrating an example of a transparent toner image generated by a transparent toner image generation unit. FIG. 3 is a diagram illustrating an example of a copy of a recording medium output by an image forming apparatus. It is a flowchart which shows a present Example.

Claims (4)

Image input means for inputting image data, image processing means for performing image processing on the image data input by the image input means, and video data for counting video data of images processed by the image processing means A plurality of developments filled with a counting means, a toner amount calculating means for calculating the amount of toner used from the video data counting means, one or more image carriers, a plurality of colored toners, and a colorless toner containing a visible light absorbing material And an exposure unit that performs exposure for forming an electrostatic latent image on the image carrier, and an image forming unit that develops the image carrier exposed by the exposure unit with the developing unit to form an image. And an image forming apparatus that prints and outputs an image formed by the image forming unit on an image recording medium,
When the toner amount of the colored toner image calculated by the toner amount calculation means exceeds a threshold value indicating a limit value, image formation for limiting the toner amount of the colorless toner image is performed. .   2. The image forming apparatus according to claim 1, wherein the area where the colorless toner image is formed is any one of a character area, an image area, and a character / image area of the colored toner image.   3. The image forming apparatus according to claim 1, further comprising setting means for a user to set a region where a colorless toner image is formed.   The image forming apparatus according to claim 1, wherein the colorless toner is a transparent toner.

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